Handle MultiRead return status

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### Expected behavior
In ```BlockBasedTable::RetrieveMultipleBlocks```, the return status of the ```MultiRead``` call should be handled - https://github.com/facebook/rocksdb/blob/master/table/block_based/block_based_table_reader.cc#L1696. In case of error, the error status should be reflected in each of the read requests.

### Actual behavior
The return status is ignored.

### Steps to reproduce the behavior
Read the code.